Cellulose copolymers that modify fibers and surfaces and methods of making same

ABSTRACT

Cellulosic polymers, copolymers and grafts, are disclosed that adhere to fibers and surfaces during an aqueous treatment process. The cellulosic polymers having grafts and/or co-blocks are prepared using living-type free radical polymerization techniques, which provides control over the degree of substitution and graft/co-block composition and structure. These cellulosic polymers allow for the modification of fibers and surfaces to provide a desired effect.

FIELD OF THE INVENTION

[0001] The present invention relates to novel polymers that are based ona cellulose backbone and grafted with a controlled number of grafts ofcontrolled length. These novel polymers are prepared by radicalpolymerization techniques, which can control the architecture of thepolymer.

BACKGROUND OF THE INVENTION

[0002] The grafting of synthetic polymers onto a cellulosic backbone hasbeen the subject of research activities for a long time. The hope is tocapture the benefits of a polymer that has properties of both celluloseand the synthetic polymers. Enormous research and development effortshave occurred over the last 40 years, but no commercializable polymer orprocess has yet been discovered, despite optimistic predictions.

[0003] The grafting of polymers on a cellulosic backbone proceedsthrough radical polymerization wherein an ethylenic monomer is contactedwith a soluble or insoluble cellulosic material together with a freeradical initiator. The radical thus formed reacts on the cellulosicbackbone (usually by proton abstraction), creates radicals on thecellulosic chain, which subsequently react with monomers to form graftchains on the cellulosic backbone. Related techniques use other sourcesof radical such high energy irradiation or oxydising agents such asCerium salt, or redox system such as thiocarbonate-potassium bromate.These method are well known, see, e.g., Mc Donald, et al. Prog. Polym.Sci. 1984, 10, 1; Hebeish et al. “The Chemistry and Technology ofcellulosic copolymers”, (Springer Verlag, 1981); Samal et al. J.Macromol. Sci-Rev. Macromol. Chem, 1986, 26, 81; Waly et al, Polymers &polymer composites 4, 1, 53, 1996; and D. Klenn et al., ComprehensiveCellulose Chemistry, vol. 2 “Functionalization of Cellulose” pp. 17-31(Wiley-VCH, Weinheim, 1998); each of which is incorporated herein byreference.

[0004] Another strategy involves functionalizing the cellulose backbonewith a reactive double bond and polymerizing in presence of monomersunder conventional free radical polymerization conditions, see, e.g.,U.S. Pat. No. 4,758,645. Alternatively a free radical initiator iscovalently linked to the polysaccharide backbone to generate a radicalfrom the backbone to initiate polymerization and form graft copolymers(see, e.g., Bojanic V, J, Appl. Polym. Sci., 60, 1719-1725, 1996 andZheng et al, ibid, 66, 307-317, 1997). For example, in U.S. Pat. No.4,206,108, a thiol is covalently bound to a polymeric backbone withpendent hydroxy groups via an urethane linkage; this polymer containingmercapto groups is reacted with ethylenically unsaturated monomers toform the graft copolymer.

[0005] However, none of these techniques lead to a well-defined materialwith a controlled macrostructure and microstructure. For instance noneof these techniques lead to a good control of both the number of graftschains per cellulose backbone molecule and molecular weight of the graftchains. Moreover side reactions are difficult, if not impossible, toavoid, including the formation of un-grafted polymer, graft chaindegradation and/or crosslinking of the grafted chains.

[0006] To solve these problems, pre-formed chains have been chemicallygrafted onto cellulosic polymers. For instance, in U.S. Pat. No.4,891,404 polystyrene chains were grown in an anionic polymerization andcapped with, e.g., CO₂. These grafts were then attached to mesylated ortosylated cellulose triacetate by nucleophilic displacement. This methodis difficult to commercialize because of the stringent conditionsrequired by the method. Moreover, the set of monomers that can be usedin this method is restricted to non-polar olefins, namely precluding anyapplication in water media.

[0007] Block copolymers based on cellulose esters have been reported.See, e.g., Oliveira et al, Polymer, 35, 9, 1994; Feger et al, PolymerBulletin, 3, 407, 1980; Feger et al, Ibid, 6, 321, 1982; U.S. Pat. No.3,386,932; Steinmann, Polym. Preprint, Am. Chem. Soc. Div. Polym. Chem.1970, 11, 285; Kim et al., J. Polym. Sci. Polym. Lett. Ed., 1973, 11,731; and Kim et al., J. Macromol. Sci., Chem. (A) 1976, 10, 671, each ofwhich is incorporated herein by reference. A major problem with thesereferences is the generation of considerable chain branching, graftingor crosslinking. Mezger et al., Angew. Makromol. Chem., 116, 13, 1983prepared oligomeric monohydroxy-terminated cellulose coupled with4-4′diphenyl-disocyanate, which was then used as aUV-macro-photo-initiator to prepare triblock copolymers. The reaction isknown as the iniferter technique and uses UV initiation, which limitsits applicability to certain processing methods and furthermore istypically applicable to styrenic and methacrylic monomers. Othermonomers, such as acrylics, vinyl acetate, acrylamide type monomers,which are in widespread use in waterborne systems, might require anothertechnique.

[0008] Previously, it has been recognized in the art that cellulosebased materials adhere to cotton fibers. For example, WO 00/18861 and WO00/18862 disclose cellulosic compounds having a benefit agent attached,so that the benefit agent will be attached to the fiber. See also WO99/14925. However, the ability of cellulose based materials to adherehas not been fully investigated, and a need exists to find cellulosicbased materials that are of commercial significance.

[0009] Therefore, there is a strong need to develop a process that makesit possible to prepare either block or grafted materials from cellulosicpolymers, with a predictable number of blocks or graft chains percellulosic backbone in a waterborne system. These blocks and graftchains should be controlled in length and chemical composition.Moreover, the method of synthesis should be commercializable.Furthermore, a need exists to provide benefits to fibers and surfaces.

SUMMARY OF THE INVENTION

[0010] This invention solves, at least in part, these needs by providinga process that can be implemented under conditions similar toconventional polymerization, which is applicable to a large of varietyof hydrophilic and hydrophobic monomers. This invention provides aliving or controlled free radical method of preparing cellulosic graftpolymers by attaching a free radical control agent to a controllednumber of sites on a cellulose backbone, where the cellulose backbonehas been sized to a desired degree of polymerization. The grafts arethen grown to a desired size using living-type kinetics, with the graftsbeing chosen from a wide variety of one or more monomers. When thegrafts are located at one or more terminal end portions of thecellulosic backbone, then the polymers are considered herein to be blockcopolymers.

[0011] The cellulosic grafted and copolymeric materials of thisinvention with well-defined macromolecular features find utility in awide field of applications. In particular, due to their segmentedstructures, these polymers have applicability as compatibilizers betweennaturally occurring bio-polymers such as starch or cellulose withsynthetic thermoplastic resins, so-called biodegradable bio-plastics.

[0012] Furthermore, the polymers of this invention may be water soluble,or at least water-dispersible (e.g., water swellable). In some of theseembodiments, the cellulosic moiety is known to adsorb to cellulosicsurface, such as cotton or paper, which then alter the surface orinterface of cotton/paper and bring new benefits to the fiber orsurface.

[0013] The process of this invention has a number of benefits, which canbe considered objects of this invention, including (1) control of themolecular weight of the cellulosic backbone through the depolymerizationprocess, (2) little or no significant side reactions that leads tocrosslinking or chain severing of the cellulosic backbone, (3) controlof the grafting site density, (4) control of the graft or block length,(5) minimization of ungrafted material, and (6) control of the graft orblock chemical composition (e.g., high chain homogeneity as compared toconventional free radical processes).

[0014] It is another aspect and object of this invention to providecellulosic backbone polymers that have a controlled degree of graftsubstitution.

[0015] It is an object of this invention to prepare cellulosic graftpolymers by growing grafts with living kinetics from a cellulosicbackbone.

[0016] It is another object of this invention to provide a method ofpreparing cellulosic graft polymers.

[0017] It is yet another object of this invention to provide cellulosicgraft polymers that adhere to fibers or surfaces, preferably in thepresence of water.

[0018] It is a further object of this invention to modify a cotton orpaper fiber or surface in an aqueous treatment step.

[0019] It is still a further object of this invention to modify a cottonor paper fiber or surface with a cellulosic graft polymer having knownproperties.

[0020] Further aspects and objects of this invention will be evident tothose of skill in the art upon review of this specification.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021]FIG. 1 is a schematic drawing of the processes of this inventionfor preparation of grafted cellulosic materials and copolymericmaterials.

[0022]FIG. 2 is a block diagram showing the various routes for employinghydrolysis or saponification in the preparation of cellulosic grafted orcopolymeric materials.

[0023]FIG. 3 is a graft of a calibration plot in connection with Example2.

[0024]FIG. 4 is a graft showing the relationship between graft length incellulosic graft polymer to adsorbancy on to cotton fibers.

[0025]FIGS. 5A and 5B are each graphs showing selected experimentalresults from Example 3, with FIG. 5A showing the amount of cellulosicgraft THMMA polymer with a degree of substitution of 0.023 depositedonto cotton fibers after a treatment process and Figure showing resultsof a similar experiment showing the amount of cellulosic graft THMMApolymer with a degree of substitution of 0.18 deposited onto cottonfibers after a treatment process.

[0026]FIG. 6 is a plot of grafts per chain versus graft degree ofpolymerization from Example 3.

DETAILED DESCRIPTION OF THE INVENTION

[0027] This invention applies living-type kinetics to the grafting ofsynthetic polymers to cellulosic polymeric backbones. This novelmethodology leads to the production of controlled architecture graftcopolymers having unique properties. At least one of the uniqueproperties discovered has been a graft cellulosic polymer that adheresto a fiber or surface during an aqueous treating step. In particular ithas been found that the cellulose graft polymers of the currentinvention adhere to cotton fibers during an aqueous treatment step andare not removed during subsequent treatment of the cotton fibers. Thus,the cellulosic polymers of the present invention find utility inmodifying fibers or surfaces (e.g., cotton or paper) to impart abenefit, such as hydrophilicity, hydrophobicity, oleophobicity,adhesion, sensory effects, wetability, lubrication, tensile strength,preservation, anti-staining properties, etc. The imparted benefit can bechosen depending on the intended use of the fiber or surface. Thoseskilled in the art will understand that additional utilities, such asthose mentioned above, are readily apparent.

[0028] It is to be understood that the terminology used herein is forthe purpose of describing particular embodiments only, and is notintended to be limiting. As used in this specification and the appendedclaims, the singular forms “a,” “an” and “the” include plural referentsunless the context clearly dictates otherwise. In describing andclaiming the present invention, the following terminology will be usedin accordance with the definitions set out below. These definitions areintended to supplement and illustrate, not preclude, the definitionsknown to those of skill in the art.

[0029] The following definitions pertain to chemical structures,molecular segments and substituents:

[0030] As used herein, the phrase “having the structure” is not intendedto be limiting and is used in the same way that the term “comprising” iscommonly used. The term “independently selected from the groupconsisting of” is used herein to indicate that the recited elements,e.g., R groups or the like, can be identical or different (e.g., R² andR³ in the structure of formula (1) may all be substituted alkyl groups,or R² may be hydrido and R³ may be methyl, etc.).

[0031] “Optional” or “optionally” means that the subsequently describedevent or circumstance may or may not occur, and that the descriptionincludes instances where said event or circumstance occurs and instanceswhere it does not. For example, the phrase “optionally substitutedhydrocarbyl” means that a hydrocarbyl moiety may or may not besubstituted and that the description includes both unsubstitutedhydrocarbyl and hydrocarbyl where there is substitution.

[0032] The term “alkyl” as used herein refers to a branched orunbranched saturated hydrocarbon group typically although notnecessarily containing 1 to about 24-6carbon atoms, such as methyl,ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, octyl, decyl,and the like, as well as cycloalkyl groups such as cyclopentyl,cyclohexyl and the like. Generally, although again not necessarily,alkyl groups herein contain 1 to about 12 carbon atoms. The term “loweralkyl” intends an alkyl group of one to six carbon atoms, preferably oneto four carbon atoms. “Substituted alkyl” refers to alkyl substitutedwith one or more substituent groups, and the terms“heteroatom-containing alkyl” and “heteroalkyl” refer to alkyl in whichat least one carbon atom is replaced with a heteroatom.

[0033] The term “alkenyl” as used herein refers to a branched orunbranched hydrocarbon group typically although not necessarilycontaining 2 to about 24 carbon atoms and at least one double bond, suchas ethenyl, n-propenyl, isopropenyl, n-butenyl, isobutenyl, octenyl,decenyl, and the like. Generally, although again not necessarily,alkenyl groups herein contain 2 to about 12 carbon atoms. The term“lower alkenyl” intends an alkenyl group of two to six carbon atoms,preferably two to four carbon atoms. “Substituted alkenyl” refers toalkenyl substituted with one or more substituent groups, and the terms“heteroatom-containing alkenyl” and “heteroalkenyl” refer to alkenyl inwhich at least one carbon atom is replaced with a heteroatom.

[0034] The term “alkynyl” as used herein refers to a branched orunbranched hydrocarbon group typically although not necessarilycontaining 2 to about 24 carbon atoms and at least one triple bond, suchas ethynyl, n-propynyl, isopropynyl, n-butynyl, isobutynyl, octynyl,decynyl, and the like. Generally, although again not necessarily,alkynyl groups herein contain 2 to about 12 carbon atoms. The term“lower alkynyl” intends an alkynyl group of two to six carbon atoms,preferably three or four carbon atoms. “Substituted alkynyl” refers toalkynyl substituted with one or more substituent groups, and the terms“heteroatom-containing alkynyl” and “heteroalkynyl” refer to alkynyl inwhich at least one carbon atom is replaced with a heteroatom.

[0035] The term “alkoxy” as used herein intends an alkyl group boundthrough a single, terminal ether linkage; that is, an “alkoxy” group maybe represented as —O-alkyl where alkyl is as defined above. A “loweralkoxy” group intends an alkoxy group containing one to six, morepreferably one to four, carbon atoms. The term “aryloxy” is used in asimilar fashion, with aryl as defined below.

[0036] Similarly, the term “alkyl thio” as used herein intends an alkylgroup bound through a single, terminal thioether linkage; that is, an“alkyl thio” group may be represented as —S-alkyl where alkyl is asdefined above. A “lower alkyl thio” group intends an alkyl thio groupcontaining one to six, more preferably one to four, carbon atoms.

[0037] The term “allenyl” is used herein in the conventional sense torefer to a molecular segment having the structure —CH═C═CH₂. An“allenyl” group may be unsubstituted or substituted with one or morenon-hydrogen substituents.

[0038] The term “aryl” as used herein, and unless otherwise specified,refers to an aromatic substituent containing a single aromatic ring ormultiple aromatic rings that are fused together, linked covalently, orlinked to a common group such as a methylene or ethylene moiety. Thecommon linking group may also be a carbonyl as in benzophenone, anoxygen atom as in diphenylether, or a nitrogen atom as in diphenylamine.Preferred aryl groups contain one aromatic ring or two fused or linkedaromatic rings, e.g., phenyl, naphthyl, biphenyl, diphenylether,diphenylamine, benzophenone, and the like. In particular embodiments,aryl substituents have 1 to about 200 carbon atoms, typically 1 to about50 carbon atoms, and preferably 1 to about 20 carbon atoms. “Substitutedaryl” refers to an aryl moiety substituted with one or more substituentgroups, (e.g., tolyl, mesityl and perfluorophenyl) and the terms“heteroatom-containing aryl” and “heteroaryl” refer to aryl in which atleast one carbon atom is replaced with a heteroatom.

[0039] The term “aralkyl” refers to an alkyl group with an arylsubstituent, and the term “aralkylene” refers to an alkylene group withan aryl substituent; the term “alkaryl” refers to an aryl group that hasan alkyl substituent, and the term “alkarylene” refers to an arylenegroup with an alkyl substituent.

[0040] The terms “halo” and “halogen” are used in the conventional senseto refer to a chloro, bromo, fluoro or iodo substituent. The terms“haloalkyl,” “haloalkenyl” or “haloalkynyl” (or “halogenated alkyl,”“halogenated alkenyl,” or “halogenated alkynyl”) refers to an alkyl,alkenyl or alkynyl group, respectively, in which at least one of thehydrogen atoms in the group has been replaced with a halogen atom.

[0041] The term “heteroatom-containing” as in a “heteroatom-containinghydrocarbyl group” refers to a molecule or molecular fragment in whichone or more carbon atoms is replaced with an atom other than carbon,e.g., nitrogen, oxygen, sulfur, phosphorus or silicon. Similarly, theterm “heteroalkyl” refers to an alkyl substituent that isheteroatom-containing, the term “heterocyclic” refers to a cyclicsubstituent that is heteroatom-containing, the term “heteroaryl” refersto an aryl substituent that is heteroatom-containing, and the like. Whenthe term “heteroatom-containing” appears prior to a list of possibleheteroatom-containing groups, it is intended that the term apply toevery member of that group. That is, the phrase “heteroatom-containingalkyl, alkenyl and alkynyl” is to be interpreted as“heteroatom-containing alkyl, heteroatom-containing alkenyl andheteroatom-containing alkynyl.”

[0042] “Hydrocarbyl” refers to univalent hydrocarbyl radicals containing1 to about 30 carbon atoms, preferably 1 to about 24 carbon atoms, mostpreferably 1 to about 12 carbon atoms, including branched or unbranched,saturated or unsaturated species, such as alkyl groups, alkenyl groups,aryl groups, and the like. The term “lower hydrocarbyl” intends ahydrocarbyl group of one to six carbon atoms, preferably one to fourcarbon atoms. “Substituted hydrocarbyl” refers to hydrocarbylsubstituted with one or more substituent groups, and the terms“heteroatom-containing hydrocarbyl” and “heterohydrocarbyl” refer tohydrocarbyl in which at least one carbon atom is replaced with aheteroatom.

[0043] By “substituted” as in “substituted hydrocarbyl,” “substitutedaryl,” “substituted alkyl,” “substituted alkenyl” and the like, asalluded to in some of the aforementioned definitions, is meant that inthe hydrocarbyl, hydrocarbylene, alkyl, alkenyl or other moiety, atleast one hydrogen atom bound to a carbon atom is replaced with one ormore substituents that are functional groups such as hydroxyl, alkoxy,thio, phosphino, amino, halo, silyl, and the like. When the term“substituted” appears prior to a list of possible substituted groups, itis intended that the term apply to every member of that group. That is,the phrase “substituted alkyl, alkenyl and alkynyl” is to be interpretedas “substituted alkyl, substituted alkenyl and substituted alkynyl.”Similarly, “optionally substituted alkyl, alkenyl and alkynyl” is to beinterpreted as “optionally substituted alkyl, optionally substitutedalkenyl and optionally substituted alkynyl.”

[0044] As used herein the term “silyl” refers to the —SiZ¹Z²Z³ radical,where each of Z¹, Z², and Z³ is independently selected from the groupconsisting of hydrido and optionally substituted alkyl, alkenyl,alkynyl, aryl, aralkyl, alkaryl, heterocyclic, alkoxy, aryloxy andamino.

[0045] As used herein, the term “phosphino” refers to the group —PZ¹Z²,where each of Z¹ and Z² is independently selected from the groupconsisting of hydrido and optionally substituted alkyl, alkenyl,alkynyl, aryl, aralkyl, alkaryl, heterocyclic and amino.

[0046] The term “amino” is used herein to refer to the group —NZ¹Z²,where each of Z¹ and Z² is independently selected from the groupconsisting of hydrido and optionally substituted alkyl, alkenyl,alkynyl, aryl, aralkyl, alkaryl and heterocyclic.

[0047] The term “thio” is used herein to refer to the group —SZ¹, whereZ¹ is selected from the group consisting of hydrido and optionallysubstituted alkyl, alkenyl, alkynyl, aryl, aralkyl, alkaryl andheterocyclic.

[0048] As used herein all reference to the elements and groups of thePeriodic Table of the Elements is to the version of the table publishedby the Handbook of Chemistry and Physics, CRC Press, 1995, which setsforth the new IUPAC system for numbering groups.

[0049] The term “degree of substitution” (or DS) is used herein to referto substitution of the three hydroxyl groups on the repeatinganhydroglucose unit. DS thus takes at least two forms in thisapplication. In one form, the DS is considered with respect to a singlesugar unit, and thus, the maximum degree of substitution is 3 on anysingle sugar unit. In this first form, DS values do not generally relateto the uniformity of substitution of chemical groups along the cellulosemolecule and are not related to the molecular weight of the cellulosebackbone, unless otherwise specified. In the second form, DS refers tothe average number of substitution on all sugar units across a bulksample of graft or block copolymer. In this second form, the DS istypically less than 1 and is typically experimentally determined asdiscussed herein. Also in this second form, the DS is included in thesimple equation {(Mw backbone/Mw sugar unit)×DS}=number of grafts. Uponreview of this specification, the different usages of DS will beapparent to those of skill in the art.

[0050] “Cellulose triacetate” refers to a molecule that has acetateesters in a degree of substitution of about 2.7 to 3. “Cellulosemonoacetate” refers to a molecule that has acetate esters in a degree ofsubstitution of about 1.1 or less, preferable about 1.1 to about 0.5.

[0051] Processes for Polymer Synthesis:

[0052] The invention herein, in one aspect, is a cellulosic graftpolymer as described below. Upon identification of the polymer havingdesired properties and/or structure, those of skill in the art willrecognize various methods for producing such polymers. The variousmethods include production of telechelic grafts and subsequentattachment to a cellulosic backbone and attachment of control agents orinitiators to the cellulosic backbone for the free radicalpolymerization of the graft segments (preferably in a living orcontrolled manner). In another aspect, the invention is a cellulosiccopolymer, which is prepared from control agents for the living orcontrolled free radical polymerization of monomers into blocks. Thepreferred method of production of these two categories of polymers isgenerally shown in FIG. 1. As shown therein, a cellulosic startingmaterial (e.g., cellulosic backbone) is optionally first depolymerizedto a desired size. Then following route a in FIG. 1, initiator controlagents (designated herein as Y) are attached to at least some middleportions of the cellulosic material. Following route b in FIG. 1,initiator-control agents are attached to at least one terminal endportion of the cellulosic backbone. Desired one or more monomers arethen polymerized in a controlled or living-type free radical method toyield cellulosic backbone graft polymers from route a and blockcopolymers from route b, with the rectangular blocks representing thegraft or block polymer segments.

[0053]FIG. 2 shows the processes for synthesis of the polymers of thisinvention in block diagram form. As shown in FIG. 2, the cellulosicstarting material is optionally, but typically, depolymerized to obtaina cellulosic material having a desired size. Thereafter, the processproceeds in one of two routes. In a first route, after depolymerizationthe cellulosic material is optionally subjected to hydrolysis orsaponification, depending on the starting material. The purpose ofhydrolysis or saponification is to make the cellulosic material morewater soluble (or at least water dispersible by reducing the degree ofsubstitution, as explained more fully below). Following the same firstroute, the cellulosic material is substituted with one or moreinitiator-control agents. The substituted material is then subjected topolymerization conditions with one or more monomers or choice in orderto polymerize the one or more monomers at the points of attachment ofthe initiator control agents. This polymerization step is preferablyperformed under living or controlled type kinetics (although some lossof control is conceivable). The alternative second route shown in FIG. 2is where the hydrolysis or saponification step is performed after thepolymerization step and is an alternative depending on the startingcellulosic material.

[0054] Therefore, cellulosic-based polymers, which are an object of thisinvention, can be prepared according to the general schemes indicated inFIG. 2. Basically they can be graft copolymers composed of a cellulosicbackbone and synthetic polymeric chains grafted to it, or blockcopolymers wherein the cellulosic segment is linked to another syntheticpolymeric chain at either one or both ends. Block copolymers areprepared according the same scheme with the exception that the controlagents are selectively anchored to the termini of the cellulosic chains.

[0055] Depolymerization

[0056] The polymers of this invention generally have a cellulosicbackbone selected from the group consisting of cellulose, modifiedcellulose and hemi-cellulose. Modified cellulose and hemi-cellulose areused herein consistently with as those of skill in the art would usesuch terms, including for example, a cellulosic materials having atleast some β-1,4-linked glucose units in the backbone, such as mannan,glucomannan and xyloglucan. The cellulosic backbone may be naturallyoccurring and may be straight chained or branched. In preferredembodiments, the cellulosic backbone is triacetate cellulose ormonoacetate cellulose. The cellulosic backbone may be obtained fromcommercial sources, but in preferred embodiments, a cellulosic backboneobtained from such sources is de-polymerized prior to preparation of thegrafts or copolymers.

[0057] Cellulosic materials are preferably those obtained from theesterification of natural or regenerated cellulose. Cellulose esterssuch as cellulose mono-, di- and tri-acetate, or as cellulose mono-, di-and tri-propionate are preferred. Depolymerization is performedaccording to known procedures. For instance, one can start frommicrocrystalline cellulose, that is successively hydrolyzed in fumingHCI in cellulose oligomers, then isolated and re-acetylated intriacetate cellulose (Flugge L. A et al., J. Am. Chem. Soc. 1999, 121,7228-7238). This process works well when very low molecular weights aretargeted, for example for a degree of polymerization of about 8 andbelow. Other processes start from cellulose esters with a DS between 2.7and 3 (e.g., fully esterified cellulose), which are contacted eitherwith Bronsted acid, such as HBr (De Oliveira W. et al., Cellulose, 1994,1, 77-86), or Lewis acid such as BF₃ (U.S. Pat. No. 3,386,932). Each ofthese references is incorporated herein by reference. Molecular weightcontrol of the cellulosic backbone is achieved by adjusting the reactionconditions, like temperature, time of contact and concentration of theacid, etc.

[0058] Whether depolymerization is carried out or not, the cellulosicbackbone has a number average molecular weight in the range of fromabout 3,000 to about 100,000, more preferably in the range of from about3,000 to about 60,000 and most preferable in the range of from about3,000 to about 20,000. Depending on the exact type of cellulose, thedegree of polymerization can range from about 15 to about 250, morepreferably from about 15 to about 100, and most preferably from about 15to about 80.

[0059] Depending on the starting material (e.g., cellulose triacetate orcellulose monoacetate), the cellulosic backbone polymer optionally maybe hydroylzed or saponified. Hydrolysis or saponification may optionallybe performed on the graft or copolymers of this invention after thegrafts or blocks have been grown from the cellulosic backbone. Thepurpose of this step in the process is to provide water solubility ordispersability to the cellulosic graft or copolymers of this invention.The term “water soluble” as used herein means that the graft orcopolymers are either freely soluble in or dispersible (as a stablesuspension) in at least water or a buffered water solution. “Soluble”herein means that the copolymer dissolves in the solvent or solvents at25° C. at a concentration of at least about 0.1 mg/mL, preferably about1 mg/mL, more preferably about 2 mg/mL, and most preferably about 10mg/mL. Hydrolysis or saponification is carried out substantiallyaccording to methods known to those of skill in the art. Hydrolysis iscarried out by reacting the cellulosic backbone with an acid, such asacetic acid. Generally, the deacetylation/hydrolysis is carried out in amix of acetic acid, water and methanol at an appropriate temperature(e.g., about 155° C.) in an appropriate vessel (e.g., a sealed reactor).Typical reaction times are 9 to 12 hrs. The product is isolated byprecipitation into acetone and yields a water soluble/dispersible formof cellulosic material (acetate DS˜0.75-1.25). See, for example, WO00/22224, which is incorporated herein by reference. Saponification,generally, is carried out by reacting the cellulosic backbone materialwith a base, such as NaOH or KOH. Typically, a solution of thecellulosic backbone material in a solvent (e.g., dimethylformamide (DMF)or tetrahydrofuran (THF), for example in a concentration 10 to 25 weight%) is added into an aqueous solution of the base (for example, in aconcentration 0.1M to 1M preferably between 0.1M to 0.5M, attemperatures between 25° C. and 80° C., preferably between 40° C. and60° C. to make up a total polymer concentration of 10000 ppm).

[0060] The cellulosic backbone is substituted (sometimes referred to as“activated”) with a desired degree of substitution of initiator-controlagent adducts so that grafts or blocks may be polymerized or grown fromthe sites of attachment of the initiator-control agent adducts. Becausepolymerization will appear to have occurred between the bond of theinitiator and control agent, with the initiator fragment or the controlagent fragment may be attached to the cellulosic backbone, such that thesubstituted material may be characterized by the general formula:

[0061] where SU represents a sugar unit in the cellulosic material, L isan optional linker, Y is the initiator control agent adduct or chaintransfer agent (collectively generally referred to herein a “controlagent”), a is the number of sugar units that do not have a Ysubstitution and is typically in the range of from about 3-80, b is thenumber sugar units that have at least one Y substitution and istypically in the range of from about 1-25, c is 0 or 1 depending onwhether a linker is present, d is the degree of substitution of Ycontrol agents on a single sugar unit and is in the range of from about1-3. Formula I is not intended to indicate any particular order to thearrangement of the sugar units having a control agent substitution (SUb)as compared to sugar units without a control agent substitution (SUa).As discussed below, the overall DS of the control agents on thecellulosic backbone can vary. The sugar units may be placed in any order(e.g., random) and there may be many more unsubstituted sugar units(SUa) than substituted sugar units (SUb). Moreover, formula (I) showsthe middle sugar units of the cellulosic backbone, but the copolymerembodiment of this invention has the Y substituents placed on at leastone terminal end sugar unit.

[0062] In some preferred embodiments, a, b and d are numbers that willgive the graft or copolymers of this invention the desired level ofadherence to the surface or fiber. In other words, a, b and d controlthe properties of the resultant polymer. Since it is an object of thisinvention to provide a grafted or copolymers cellulosic material thatadheres to cotton or other fibers or surfaces, then control of a, b andd may be critical to the invention.

[0063] As those of skill in the art will appreciate, a and b aretypically determined from a bulk sample by nuclear magnetic resonance(NMR), gel permeation chromatography (GPC) or some other spectroscopicor chromatographic technique. Thus, a and b may be average numbersacross the bulk sample and they may not be integers. Using formula (I),the number of grafts per chain is calculated by multiplying b times d.And, the graft density for a bulk sample (which is sometimes referred toherein as the degree of substitution of grafts or graft DS) isdetermined by the formula (b*d)/(a+b), where the average graft densityfor a bulk sample is determined by NMR or another spectroscopictechnique and (a+b) is determined on average by GPC or anotherchromatographic technique. These two measurements will allow forcalculation of the number of grafts per chain (b*d). In someembodiments, graft density for a bulk sample (i.e., the DS of graftchains in the bulk sample) is in the range of from about 0.005 to about3, more preferably in the range of from about 0.01 to about 1 and evenmore preferably in the range of from about 0.05 to about 0.15. Onespecific method for experimentally determining the DS of the grafts isby proton NMR. In this approach, the integrated area under the peak isdivided by the expected number of protons for both the control agent andthe sugar units. These numbers are used to create a ratio of controlagent to sugar unit, which is considered to be the degree ofsubstitution of the control agents in the bulk sample. This is themethodology used in the examples, below.

[0064] The number of grafts per chain is preferably in the range of fromabout 1 to about 75 and more preferably in the range of from about 1 to20. Although the discussion in this paragraph is presented in terms of“grafts”, those of skill in the art will appreciate that this samediscussion applies to the degree of substitution of control agents inthe bulk sample (e.g., DS of control agents is determined on a bulksample by the measurement techniques discussed herein and may berepresented by the formula (b*d)/(a+b)). In addition to the NMR, GPC andother spectroscopic techniques discussed above, the number of Yattachment points may be determined by enzymatic digestion of thecellulosic backbone to glucose. This method is known to those of skillin the art and typically involves a GPC measurement for number averagemolecular weight with a calculation to obtain the number of chains.

[0065] In formula (I), Y is the initiator control agent adduct,iniferter or chain transfer agent, which is the portion that providescontrol of the free radical polymerization process, and is thusgenerally referred to herein as the control agent (CA). This portion ofthe molecule can include an initiating portion or not, depending on themethod of polymerization being employed. One preferred embodiment iswhere Y is a control agent without an initiating fragment (i.e., -CA).When initiator fragment is present, Y may be either —I-CA or -CA-I,where CA refers to a control agent moiety or fragment and I refers to aninitiator moiety or fragment. Therefore the number of grafts can bedefined by the number of attachment points of a —I-CA or -CA group. Whenan initiating fragment is present in Y, the —I-CA embodiment isgenerally preferred.

[0066] Y is selected from those control agents that provide living-typekinetics to the polymerization of at least one monomer from the site ofattachment of the agent. Typically, the agent must be able to beexpelled as or support a free radical. In some embodiments, Y ischaracterized by the general formula:

[0067] where Z is any group that activates the C═S double bond towards areversible free radical addition fragmentation reaction and R″ isselected from the group consisting of, generally, any group that can beeasily expelled under its free radical form (R″) upon anaddition-fragmentation reaction. This control agent can be attached tothe cellulosic backbone through either Z or R″, however, for ease thesegroups are discussed below in terms as if they are not the linking groupto the cellulosic backbone (thus, e.g., alkyl would actually bealkylene). R″ is generally selected from the group consisting ofoptionally substituted hydrocarbyl, and heteroatom-containinghydrocarbyl. More specifically, R″ is selected from the group consistingof optionally substituted alkyl, aryl, alkenyl, alkoxy, heterocyclyl,alkylthio, amino and polymer chains. And still more specifically, R″ isselected from the group consisting of —CH₂Ph, —CH(CH₃)CO₂CH₂CH₃,—CH(CO₂CH₂CH₃)₂, —C(CH₃)₂CN, —CH(Ph)CN and —C(CH₃)₂Ph. Z is typicallyselected from the group consisting of hydrocarbyl, substitutedhydrocarbyl, heteroatom-containing hydrocarbyl and substitutedheteroatom containing hydrocarbyl. More specifically, Z is selected fromthe group consisting of optionally substituted alkyl, aryl, heteroaryland most preferably is selected from the group consisting of amino andalkoxy. In other embodiments, Z is attached to C═S through a carbon atom(dithioesters), a nitrogen atom (dithiocarbamate), two nitrogen atoms inseries (dithiocarbazate), a sulfur atom (trithiocarbonate) or an oxygenatom (dithiocarbonate). Specific examples for Z can be found in WO98/01478, WO99/35177, WO99/31144, WO98/58974, U.S. Pat. No. 6,153,705,and U.S. patent application Ser. No. 09/676,267, filed Sep. 28, 2000,each of which is incorporated herein by reference. Particularlypreferred control agents of the type in formula II are those where thecontrol agent is attached through R″ and Z is either, a carbazate,—OCH₂CH₃ or pyrrole attached via the nitrogen atom. As discussed below,linker molecules can be present to attach the C═S group to the cellulosebackbone through Z or R″.

[0068] In another embodiment, when the —I-CA embodiment is being used,the control agent may be a nitroxide radical. Broadly, the nitroxideradical control agent may be characterized by the general formula—O—NR⁵R⁶, wherein each of R¹ and R⁶ is independently selected from thegroup of hydrocarbyl, substituted hydrocarbyl, heteroatom containinghydrocarbyl and substituted heteroatom containing hydrocarbyl; andoptionally R⁵ and R⁶ are joined together in a ring structure. In a morespecific embodiment, the control agent may be characterized by thegeneral formula:

[0069] where I is a residue capable of initiating a free radicalpolymerization upon homolytic cleavage of the I—O bond, the I residuebeing selected from the group consisting of fragments derived from afree radical initiator, alkyl, substituted alkyl, alkoxy, substitutedalkoxy, aryl, substituted aryl, and combinations thereof; X is a moietythat is capable of destabilizing the control agent on a polymerizationtime scale; and each R¹ and R², independently, is selected from thegroup consisting of alkyl, substituted alkyl, cycloalkyl, substitutedcycloalkyl, heteroalkyl, heterocycloalkyl, substituted heterocycloalkyl,aryl, substituted aryl, heteroaryl, substituted heteroaryl, alkoxy,aryloxy, silyl, boryl, phosphino, amino, thio, seleno, and combinationsthereof; and R³ is selected from the group consisting of tertiary alkyl,substituted tertiary alkyl, aryl, substituted aryl, tertiary cycloalkyl,substituted tertiary cycloalkyl, tertiary heteroalkyl, tertiaryheterocycloalkyl, substituted tertiary heterocycloalkyl, heteroaryl,substituted heteroaryl, alkoxy, aryloxy and silyl. Preferably, X ishydrogen. Synthesis of the types of initiator-control agents in formulaIII is disclosed in, for example, Hawker et al., “Development of aUniversal Alkoxyamine for ‘Living’ Free Radical Polymerizations,” J. Am.Chem. Soc., 1999, 121(16), pp. 3904-3920 and U.S. patent applicationSer. No. 09/520,583, filed Mar. 8, 2000 and corresponding internationalapplication PCT/US00/06176, all of which are incorporated herein byreference.

[0070] Control Agent Attachment

[0071] In order to attach Y to the cellulosic backbone, a linker istypically employed (i.e., c=1), designated L in formula I. Linkers areat least dual functional molecules that will react with either ahydroxyl or acetyl ester group of the cellulosic backbone; the linkerwill also be able to react with a precursor molecule that comprises theY unit. Typically, a linker has from 2 to 50 non-hydrogen atoms. Linkers(L) may be selected from any of the molecules discussed in this section.Given the molecular weights of the cellulosic backbone and the grafts orblocks that are being added to that backbone, the length of the linkermolecule may be chosen to affect or not affect the properties of thegraft or block copolymer. In order to reduce the possibility ofaffecting the properties of the final polymer, the size of the linkermolecule may be reduced in some embodiments (e.g., lower molecularweight or steric bulk).

[0072] In some preferred embodiments of the invention, the control agentis a thio-carbonylthio derivative with the following structureZ—C(═S)—S, with the control agent is linked to the cellulosic materialvia the Z or S moiety, as discussed above in association with formulaII. For graft copolymers, several techniques are available to attach thecontrol agent to the sugar units within the chain backbone.

[0073] In a first embodiment, a di-isocyanate linker is used to attachthe control agent to the cellulosic backbone. Generally, abis-isocyanate is reacted with a cellulose ester (having a DS rangingfrom about 2.5 to 2.7) together with a catalyst, such as a catalyticamount of dibutyldilauryl tin. In some preferred embodiments, the linkeris a di-isocyanate compound, having from 8-50 non-hydrogen atoms.Isocyanates are known to react with —OH, —SH and —NH₂ groups, therebyallowing for effective linking of the cellulosic backbone with aproperly prepared control agent. Di-isocyanate linkers may becharacterized by the general formula: O═C═N—R′—N═C═O, wherein R′ isselected from the group consisting of optionally substituted alkyl andaryl. The pendant NCO groups of the bis-isocyanate are then reacted withan OH-functional control agent. Most preferred di-isocyanate linkersinclude isophrorone di-isocyanate (IPDI) and hexamethylene-disocyanate.Other useful di-isocyanate derivatives can be found in “IsocyanatesBuilding Blocks for Organic Synthesis” Aldrich commercial leaflet (POBox 355 Milkauwee, Wis. 53201 USA), which is incorporated herein byreference. An alternative process comprises forming the chloroformatederivative through phosgenation of the residual OH of the celluloseester, and then reacting the latter with an hydroxyl (or any other NCOreactive) functional control agent.

[0074] The following scheme 1 shows an embodiment of this method:

[0075] In scheme 1, some embodiments will replace CA with Y, in order toshow where the polymerization may appear to occur. When a saponificationor hydrolysis step is involved as a final step in the process (see FIG.2), then the linkage between the control agent and the cellulose esterbackbone is chosen as to resist the saponification conditions.Particularly preferred are urethane or amide linkages that tend to behydrolitically robust to saponification or hydrolysis conditions. Someexamples of CA-OH functional control agents useful in scheme 1 (withinformula II, for example) are:

[0076] Another embodiment for a linker (L) is the direct attachment ofthiocarbonyl-thio control agents to the sugar rings. Generally, in thisprocess the residual OH groups on the cellulosic backbone are firstactivated by either chlorosulfonyl acids (e.g., tosylates, mesylates, ortriflates) or acid chlorides (e.g., para-nitrophenyl chloroformate).Thereafter, the cellulosic material is treated with the metal salt ofthe corresponding thiocarbonyl-thio compound (e.g., dithiocarbonate,dithiocarbamate) to graft the desired control agents to the cellulosicbackbone. This is shown for example in the following scheme 2.

[0077] In scheme 2, Ts refers to “tosylate” and Et refers to “ethyl”.

[0078] In other preferred embodiments, block copolymers are prepared,with one of the blocks being the cellulosic material. Anchoring of thecontrol agent to at least one terminal end portion of the cellulosicmaterial is achieved selectively at the C-1 anomeric carbon of theterminal sugar unit by either reductive amination or halogenation.

[0079] In the reductive amination route, the reducing terminal glucoseresidue is converted to an amino group by reacting the cellulosicmaterials with an excess of the amine or hydroxyamine together witheither sodium borohydride or sodium cyanoborohydride. Reduction underhigh pressure of hydrogen with a Nickel Raney catalyst can also beutilized. Details of these procedures can be found in Danielson S. etal., Glycoconjugate Journal (1986) 3:363-377; Larm O. et al.,Carbohydrate Research, 58(1977) 249-251; WO 98/15566; and EP 0725 082,each of which is incorporated herein by reference. The following scheme3 presents an example of this pathway:

[0080] An amino reactive control agent is then condensed to the amineend group. Typical amino reactive groups include isocyanate,isothiocyanate, epoxy, chlorotriazine, carbonate, activated esters (suchas N-hydrosuccimide esters), and the like. Isocyanate functional controlagents are preferred and one example is given below in scheme 4:

[0081] Scheme 4 shows a pyrrole as Z (from formula II), however those ofskill in the art will appreciate that other moieties can be used in thislocation of the control agent, as discussed above (e.g., the CA-OHlisted compounds listed above).

[0082] In the halogenation route to attach the control agents to theterminal end portions of the cellulosic backbone, cellulose esters aredepolymerized in a mixture of HBr and acetic anhydride in methylenechloride as described by De Oliveira W. et al., Cellulose, 1994, 1,77-86, which is incorporated herein by reference. The terminal glycosylbromide is then displaced by the thiocarbonyl-thio salt of thecorresponding control agent, as exemplified in the following scheme 5:

[0083] Scheme 5 shows ethoxy as Z (from formula II), however those ofskill in the art will appreciate that other moieties can be used in thislocation of the control agent, as discussed above. This processtypically employs a cellulose triacetate (e.g., a fully esterifiedcellulosic material) otherwise side-reactions may occur during thecontrol agent attachment step, which may lead to branched polymers. Avariant of this process comprises hydrolyzing the bromide into OH; theOH-terminated cellulose ester is then coupled with an OH reactivecontrol agent such as described above.

[0084] In each of schemes 1-5, the following formula is employed:

[0085] wherein R is selected from the group consisting of hydrogen oracetate and * refers to either an end or additional sugar units. Alsoschemes that use the “n” designation are referring to the degree ofpolymerization, discussed herein.

[0086] Generally, the polymerization of the graft segments or blocksproceeds under polymerization conditions. Polymerization conditionsinclude the ratios of starting materials, temperature, pressure,atmosphere and reaction time. The atmosphere may be controlled, with aninert atmosphere being preferred, such as nitrogen or argon. Themolecular weight of the polymer can be controlled via controlled freeradical polymerization techniques or by controlling the ratio of monomerto initiator. The reaction media for these polymerization reactions iseither an organic solvent or bulk monomer or neat. Polymerizationreaction time may be in the range of from about 0.5 hours to about 72hours, preferably from about 1 hour to about 24 hours and morepreferably from about 2 hours to about 12 hours.

[0087] When the control agent is of formula II, the polymerizationconditions that may be used include temperatures for polymerizationtypically in the range of from about 20° C. to about 110° C., morepreferably in the range of from about 50° C. to about 90° C. and evenmore preferably in the range of from about 70° C. to about 85° C. Theatmosphere may be controlled, with an inert atmosphere being preferred,such as nitrogen or argon. The molecular weight of the polymer iscontrolled via adjusting the ratio of monomer to control agent.Generally, the ratio of monomer to control agent is in the range of fromabout 200 to about 800. A free radical initiator is usually added to thereaction mixture, so as to maintain the polymerization rate to anacceptable level. Conversely, a too high free radical initiator tocontrol agent ratio will favor unwanted dead polymer formation, namelypure homopolymers or block copolymers of unknown composition. The molarratio of free radical initiator to control agent for polymerization aretypically in the range of from about 2:1 to about 0.02:1.

[0088] When the control agent is of a nitroxide radical type (seeformula III), polymerization conditions include temperatures forpolymerization typically in the range of from about 80° C. to about 130°C., more preferably in the range of from about 95° C. to about 130° C.and even more preferably in the range of from about 120° C. to about130° C. Generally, the ratio of monomer to initiator is in the range offrom about 200 to about 800.

[0089] Initiators used in the polymerization process with a controlagent (and from which I may be derived) may be known in the art. Suchinitiators may be selected from the group consisting of alkyl peroxides,substituted alkyl peroxides, aryl peroxides, substituted aryl peroxides,acyl peroxides, alkyl hydroperoxides, substituted alkyl hydroperoxides,aryl hydroperoxides, substituted aryl hydroperoxides, heteroalkylperoxides, substituted heteroalkyl peroxides, heteroalkylhydroperoxides, substituted heteroalkyl hydroperoxides, heteroarylperoxides, substituted heteroaryl peroxides, heteroaryl hydroperoxides,substituted heteroaryl hydroperoxides, alkyl peresters, substitutedalkyl peresters, aryl peresters, substituted aryl peresters, and azocompounds. Specific initiators include BPO and AIBN. In someembodiments, as discussed above, the I fragment or residue may beselected from the group consisting of fragments derived from a freeradical initiator, alkyl, substituted alkyl, alkoxy, substituted alkoxy,aryl, substituted aryl, and combinations thereof. Different I fragmentsmay be preferred depending on the embodiment of this invention beingpracticed. For example, when the di-thio control agents as generallydescribed in formula II are employed for Y equal to

[0090] I-CA, the I fragment may be considered to be a portion of thelinker, for example, may be considered to be —CH(COOR¹⁰)— where R¹⁰ isselected from the group consisting of hydrocarbyl and substitutedhydrocarbyl, and more specifically alkyl and substituted alkyl.Initiation may also be by heat or radiation, as is generally known inthe art.

[0091] Ideally, the growth of grafts or blocks attached to thecellulosic backbone occurs with high conversion. Conversions aredetermined by NMR via integration of polymer to monomer signals.Conversions may also be determined by size exclusion chromatography(SEC) via integration of polymer to monomer peak. For UV detection, thepolymer response factor must be determined for each polymer/monomerpolymerization mixture. Typical conversions can be 50% to 100%, morespecifically in the range of from about 60% to about 90%.

[0092] Optionally, the dithio moiety of the control agent of those informula II can be cleaved by chemical or thermal ways, if one wants toreduce the sulfur content of the polymer and prevent any problemsassociated with presence of the control agents chain ends, such as odoror discoloration. Typical chemical treatment includes the catalytic orstochiometric addition of base such as a primary amine, acid oranhydride, or oxydizing agents such as hypochloride salts.

[0093] As used herein, “block copolymer” refers to a polymer comprisingat least two segments having at least two differing compositions, wherethe monomers are not incorporated into the polymer architecture in asolely statistical or uncontrolled manner. In this invention, at leastone of the blocks is a cellulosic block. Although there may be two,three, four or more monomers in a single block-type polymerarchitecture, it will still be referred to herein as a block copolymer.The block copolymers of this invention may include one or more blocks ofrandom copolymer (sometimes referred to herein as an “R” block) togetherwith one or more blocks of single monomers, so long as there is acellulosic backbone from which the blocks are centrally tied. Moreover,the random block can vary in composition or size with respect to theoverall block copolymer. In some embodiments, for example, the randomblock will account for between 5 and 80% by weight of the mass of theblock copolymer. In other embodiments, the random block R will accountfor more or less of the mass of the block copolymer, depending on theapplication. Furthermore, the random block may have a compositionalgradient of one monomer to the other (e.g., A:B) that varies across therandom block in an algorithmic fashion, with such algorithm being eitherlinear having a desired slope, exponential having a desired exponent(such as a number from 0.1-5) or logarithmic. The random block may besubject to the same kinetic effects, such as composition drift, thatwould be present in any other radical copolymerization and itscomposition, and size may be affected by such kinetics, such as Markovkinetics.

[0094] A “block” within the scope of the block copolymers of thisinvention typically comprises about 5 or more monomers of a single type(with the random blocks being defined by composition and/or weightpercent, as described above). In preferred embodiments, the number ofmonomers within a single block may be about 10 or more, about 15 ormore, about 20 or more or about 50 or more. The existence of a blockcopolymer according to this invention is determined by methods known tothose of skill in the art. For example, those of skill in the art mayconsider nuclear magnetic resonance (NMR) studies, measured increase ofmolecular weight upon addition of a second monomer to chain-extend afirst block, observation of microphase separation, including long rangeorder (determined by X-ray diffraction), microscopy and/or birefringencemeasurements. Other methods of determining the presence of a blockcopolymer include mechanical property measurements, (e.g., elasticity ofhard/soft/hard block copolymers), thermal analysis and gradient elutionchromatography (e.g., absence of homopolymer).

[0095] The grafts or additional block(s) attached to the cellulosicbackbone typically has a number average molecular weight of from 100 to10,000,000 Da (preferably from 2,000 to 200,000 Da, more preferably from10,000 to 100,000 Da) and a weight average molecular weight of from 150to 20,000,000 Da (preferably from 5,000 to 450,000 Da, more preferablyfrom 20,000 to 400,000 Da).

[0096] The monomers chosen for the grafts or blocks are typicallyselected in a manner so as to produce the desired affect on the surfaceor fiber. For example, the monomers may be chosen for their particularhydrophilic or hydrophobic characteristics.

[0097] Hydrophilic monomers include, but are not limited to, acrylicacid, methacrylic acid, N,N-dimethylacrylamide, dimethyl aminoethylmethacrylate, quaternized dimethylaminoethyl methacrylate,methacrylamide, N-t-butyl acrylamide, maleic acid, maleic anhydride andits half esters, crotonic acid, itaconic acid, acrylamide, acrylatealcohols, hydroxyethyl methacrylate, diallyldimethyl ammonium chloride,vinyl ethers (such as methyl vinyl ether), maleimides, vinyl pyridine,vinyl imidazole, other polar vinyl heterocyclics, styrene sulfonate,allyl alcohol, vinyl alcohol (such as that produced by the hydrolysis ofvinyl acetate after polymerization), salts of any acids and amineslisted above, and mixtures thereof. Preferred hydrophilic monomersinclude acrylic acid, N,N-dimethyl acrylamide, dimethylaminoethylmethacrylate, quaternized dimethyl aminoethyl methacrylate, vinylpyrrolidone, salts of acids and amines listed above, and combinationsthereof.

[0098] Hydrophobic monomers may be listed above and include, but are notlimited to, acrylic or methacrylic acid esters of C₁-C₁₈ alcohols, suchas methanol, ethanol, methoxy ethanol, 1-propanol, 2-propanol,1-butanol, 2-methyl-1-propanol, 1-pentanol, 2-pentanol, 3-pentanol,2-methyl-1-butanol, 1-methyl-1-butanol, 3-methyl-1-butanol,1-methyl-1-pentanol, 2-methyl-1-pentanol, 3-methyl-1-pentanol, t-butanol(2-methyl-2-propanol), cyclohexanol, neodecanol, 2-ethyl-1-butanol,3-heptanol, benzyl alcohol, 2-octanol, 6-methyl-1-heptanol,2-ethyl-1-hexanol, 3,5-dimethyl-1-hexanol, 3,5,5-tri methyl-1-hexanol,1-decanol, 1-dodecanol, 1-hexadecanol, 1-octa decanol, and the like, thealcohols having from about 1 to about 18 carbon atoms, preferably fromabout 1 to about 12 carbon atoms; styrene; polystyrene macromer, vinylacetate; vinyl chloride; vinylidene chloride; vinyl propionate;alpha-methylstyrene; t-butylstyrene; butadiene; cyclohexadiene;ethylene; propylene; vinyl toluene; and mixtures thereof. Preferredhydrophobic monomers include n-butyl methacrylate, isobutylmethacrylate, t-butyl acrylate, t-butyl methacrylate, 2-ethylhexylmethacryl ate, methyl methacryl ate, vinyl acetate, vinyl acetamide,vinyl formamide, and mixtures thereof, more preferably t-butyl acrylate,t-butyl methacrylate, or combinations thereof.

[0099] Polymers

[0100] The cellulosic graft or copolymers of this invention may haveproperties that can be tuned or controlled depending on the desired useof the polymer. Thus, for example, when the water solubility of thechosen graft material is low or poor and the cellulosic backbone is morewater soluble than the grafts (e.g., is cellulose mono-acetate), thenthe polymer may form micelle like structures, with the hydrophobicmaterials being attracted to each other and the more hydrophilicmaterials forming an outer ring.

[0101] Following the above procedures yields a polymer either having acellulosic backbone with grafts of controlled structure and compositionor a block copolymer or a combination of both. In some embodiments thepolymers obtained are novel, which may be characterized by the size ofthe cellulosic backbone, the number of graft chains extending from thatbackbone and the length of the graft chains. In addition, these graftsare preferably single point attached to the backbone, and in someembodiments preferably, water-soluble. Where control of thepolymerization is partially list, then some of the grafts may beconnected to several backbone chains leading to cross-linking. Watersolubility is defined above. Cross-linking may be determined for thepolymers of this application by light scattering or more specificallydynamic light scattering (DLS). Alternatively, filtration of the polymersample through an about 0.2 to 0.5 micron filter without inducing abackpressure would, for purposes of this application, indicate a lack ofcross linking in the polymer sample. Also alternatively, othermechanical methods of determining cross-linking may be use, which areknown to those of skill in the art. If a polymer passes any of thesetests, it is considered substantially free of cross-linking for thepurposes of this application, with “substantially” meaning less than orequal to about 20% cross-linked.

[0102] Using the above-described parameters, the novel polymers of thisapplication are cellulosic backboned graft polymers have a degree ofsubstitution (DS) of grafts in the bulk sample in the range of from 0.02to about 0.15. As discussed above, the DS of graft chains in the bulksample is dependant on two factors, the length of the cellulosicbackbone and number of grafts. Generally, to fit the preferred DS, thecellulosic backbone typically has a molecular weight in the range offrom about 10,000 to about 40,000 and the number of grafts can rangefrom about 3 to 12. The general calculation to determine these numbersis that the molecular weight (e.g., either number average or weightaverage) of the cellulosic backbone is divided by the molecular weightof each sugar unit. This yields the number of sugar units, which is thenmultiplied by the degree of substitution in the bulk sample to yieldnumber of grafts per cellulosic backbone. In formula form, this is {(Mwbackbone/Mw sugar unit)×DS}=number of grafts. The grafts on thecellulosic backbone have a length (i.e., degree of polymerization) ofbetween 25 and 200 monomer units and more preferably between 50 and 100monomer units.

[0103] The cellulosic backbone is most preferably cellulose monoacetate,but the other cellulosic backbones are not excluded. The grafts can beselected from any of the above-listed monomers and depend on the end useof the polymer. As shown in the examples, the polymers that have thisstructure tend to have properties that allow for improved adsorption tosurfaces and fibers.

EXAMPLES

[0104] General: In the examples of this invention, syntheses in inertatmospheres were carried out under a nitrogen or argon atmosphere. Otherchemicals were purchased from commercial sources and used as received,except for monomers, which were filtered through a short column of basicaluminum oxide to remove the inhibitor and degassed by applying vacuum.Size Exclusion Chromatography was performed using automated rapid GPCsystem. In the current setup N,N-dimethylformamide containing 0.1% oftrifluoroacetic acid was used as an eluent and polystyrene-basedcolumns. All of the molecular weight results obtained are relative tolinear polystyrene standards. H¹ NMR was carried out using a Brukerspectrometer (300 MHz) with CDCl₃ (chloroform-d) as solvent.

Example 1 Preparation of Grafted Polymers

[0105] Parts A-C of this example proceeds substantially according to thefollowing scheme 6:

[0106] Part A: Synthesis of the Control Agent:

[0107] 2-Bromopropionyl bromide 1 reacted with N-silyl protectedethanolamine to form the corresponding amide. Subsequently deprotectionof silyl group occurred in acidic medium during the workup to give theN-hydroxyethyl 2-bromoacrylamide 2 in a quantitative yield. With nofurther purification, compound 2 was coupled with sodium dithiocarbamateto yield a yellow solid (“Control agent”) compound 3 in 75% yield. Allcompounds were characterized by ¹H NMR.

[0108] Part B: Depolymerization of the Cellulosic Backbone

[0109] 50 g of cellulose triacetate (“CTA”) (purchased from Aldrich,with a degree of substitution of about 2.7) was dissolved in 1000 ml ofdichloroethane (purchased from Aldrich and used without any furtherpurification) under inert atmosphere and heated to 70° C. with vigorousstirring. To this solution 0.5 ml of BF₃.Et20 was added as a solution in5 ml of dichloromethane. The mixture was stirred at 70° C. and thereaction was monitored by gel permeation chromatography (GPC). When thedesired molecular weight was achieved (about 20,000 number averagemolecular weight (Mn)), the reaction was quenched with triethyl amineand allowed to cool to room temperature. The product was isolated byprecipitation into ethyl ether or methanol or acetone or ethyl acetate.The product was purified by dissolution in THF and re-precipitation fromethyl ether. The product is characterized by H¹ NMR and GPC.

[0110] Part C: Attachment of Control Agent to Cellulosic Backbone

[0111] Attachment of control agent one end of the linker: 15 g of thecontrol agent (from part A, above) was suspended in 150 ml of drydichloromethane under an inert atmosphere. 50 ml of the dichloromethanewas distilled off and the mixture was cooled to room temperature. 21 mlof hexane diisocyanate was added to the reaction followed by 200 μl ofdibutyltin dilaurate. The reaction was stirred at room temperature for15 min. The reaction mixture was then transferred into 1000 ml of dryhexane using a cannula. This mixture was stirred for 10 min andfiltered. The residue was dissolved in dichloromethane andre-precipitated. The residue was isolated by filtration and dried undervaccum. This produces a control agent attached to one end of the linker,referred to as “control agent-linker.”

[0112] 20 g of depolymerized cellulose triacetate (Mn 20,000 from partB, above) was supended in 100 ml of benzene. The mixture was thendistilled to dryness under atmospheric pressure to azeotropically removewater from the cellulose triacetate. 100 ml of dry Dichloromethane wasadded to the vessel and 50 ml was removed by distillation. 2.5 g of thecontrol agent-linker from the previous paragraph was added to thereaction followed by 200 μl of dibutyl dilaurate. The mixture was thenstirred at 40° C. for 12 hrs. After this, the reaction mixture wascooled to room temperature, diluted to 150 ml with dichloromethane andprecipitated by pouring into methanol. The residue was isolated byfiltration and purified by re-precipitation from THF into methanol. Theproduct was characterized by H¹ NMR and GPC.

[0113] Part D: Controlled Polymerization of Vinyl Monomers onto theCellulosic Backbone:

[0114] Polymerization is carried out in a glove box with an inertatmosphere. The control agent modified cellulosic backbone (from part C)is dissolved in degassed dimethylformamide (DMF). To this, the desiredvinyl monomer or monomers are added followed by azo-bis-isobutyronitrile(AIBN). The vial is then sealed and the contents stirred at about 60° C.for about 18 hrs.

[0115] The following Table 1 describes the synthesis of 20 polymers ofdimethlacrylamide and/or acrylic acid grafted onto a cellulosic backbone(M_(n) about 20,000) modified with xanthate control agent (with Z═—OEt(see Scheme 6, above) and with about 5.7 control agents per chain, asmeasured by NMR). Assuming a number average molecular weight of about20,000, these polymers have a degree of substitution (DS) of about0.057. The length of the grafts is controlled by the weight ratio ofmonomer to cellulosic backbone. The reactants are listed in milligramsand the reactions were carried out in 1 ml vials in accord with theabove-described procedure. TABLE 1 Cta-20K-hdi-5.7-A Acrylic acidDimethyl acrylamide AIBN DMF 1 50 1.25 23.75 0.117 174.8805 2 50 6.2518.75 0.117 174.8805 3 50 12.5 12.5 0.117 174.8805 4 50 18.75 6.25 0.117174.8805 5 50 23.75 1.25 0.117 174.8805 6 50 2.5 47.5 0.117 233.213 7 5012.5 37.5 0.117 233.213 8 50 25 25 0.117 233.213 9 50 37.5 12.5 0.117233.213 10 50 47.5 2.5 0.117 233.213 11 25 2.5 47.5 0.0585 174.939 12 2512.5 37.5 0.0585 174.939 13 25 25 25 0.0585 174.939 14 25 37.5 12.50.0585 174.939 15 25 47.5 2.5 0.0585 174.939 16 25 5 95 0.0585 291.60417 25 25 75 0.0585 291.604 18 25 50 50 0.0585 291.604 19 25 75 25 0.0585291.604 20 25 95 5 0.0585 291.604

[0116] At the end of the reaction, polymers were obtained in each caseand the mixtures were diluted to a concentration of about 16.6% polymerin DMF.

[0117] Part E: Saponification:

[0118] Saponification of the cellulosic backbone is carried out bystarting with a about 16.6% of polymer in DMF added into 0.25M NaOH andstirred at 50° C. This was stirred for 30 minutes and thereafter cooledto room temperature.

Example 2 Demonstration of Adsorption to Cotton and Effect ofArchitecture on the Adsorbed Amount

[0119] Eight samples of polydimethylacrylamide grafted on cellulosemonoacetate (CMA) were prepared substantially according to the methodsof Example 1. In this example, the control agent was one where “Z” waspyrrole (see scheme 6, above). The number of grafts and length werevaried. A small amount of a fluorescent

[0120] monomer, having the structure:

[0121] was incorporated in the grafts during polymerization of thedimethylacrylamide monomer. The following conditions were employed:

[0122] Molecular weight of CMA (Mn)˜20,000 (rough approximation)

[0123] DS of control agent 0.075 and 0.15 onto the CMA

[0124] CMA:Monomer weight ratio varies from 1:2 to 1:16

[0125] Amount of fluorescent monomer: 0.75 mg in each sample

[0126] Total amount of polymer: 150.75 mg

[0127] Total solids concentration: 33.33%

[0128] Amount of AIBN: 10 mole % compared to control agent.

[0129] Reaction temperature: 60° C.

[0130] Reaction time: 18 hrs

[0131] Table 2 shows the amounts used in the polymerization mixtures:The grafts on the eight samples where polymerized in the followingratios, where “CMA-DS-0.075” represents cellulose monoacteate with adegree of substitution of 0.075 control agent in the cellulosic backbone(a graft density of 6 grafts per cellulosic backbone was measured byNMR) and “CMA-DS-0.15” represents cellulose monoacteate with a degree ofsubstitution of 0.15 control agent in the cellulosic backbone (a graftdensity of 12 grafts per cellulosic backbone was measured by NMR): TABLE2 CMA-DS-0.15 CMA-DS-0.075 DMF Dimethyl acrylamide (mg) (mg) (mg) (mg) 1— 50 350 100 2 — 30 350 120 3 — 16.67 350 133.33 4 — 8.82 350 141.18 550 — 350 100 6 30 — 350 120 7 16.67 — 350 133.33 8 8.82 — 350 141.18

[0132] Each polymerization resulted in a cellulose monoacetate graftpolydimethylacrylamide polymer. The amount of dimethylacrylamide in thepolymerization mixture determined the graft length.

[0133] The polymers were diluted in two steps to achieve a concentrationof 200 ppm by weight in a buffered surfactant solution. The compositionof the surfactant solution is as follows, with the solvent beingdemineralized water:

[0134] 0.6 g/L LAS anionic surfactant (made from the reaction ofdodecylbenzene sulphonic acid (e.g., Petrelab 550 available fromPretresa) and sodium hydroxide (e.g., available from Aldrich) resultingin a ca. 50 wt. % (in water) solution of the sodium salt of the acid,which is referred to as “LAS”).

[0135] 0.4 g/L R(EO)₇ (

[0136] 1.25 g/L Na₂CO₃— JT Baker #3604-01

[0137] 0.66 g/L STP (sodium triphosphate, available from Aldrich).

[0138] 0.6 g/L NaCl

[0139] 0.0882 g/L CaCl₂ 2H₂O—Sigma #C-8106

[0140] pH=10.5.

[0141] The polymers were prepared at a nominal concentration of 30 wt %solids in DMF, and were used without any subsequent purification toremove solvent, unreacted monomer, etc. In the first dilution step, 66μl of each crude reaction mixture was added to 2 ml of the surfactantsolution, in a 2 ml capacity 96-well polypropylene microtiter plate.This gave an initial dilution of 1:30, or a polymer concentration of 1%w/v. The solutions were mixed by repeated aspiration and dispensing froma pipette into the well of the microtiter plate. In the second dilutionstep, 40 μl of the 1% w/v solutions were added to 2 ml of the surfactantsolution in a second microtiter plate and mixed, giving an additionalfactor of 50 dilution and a final concentration of 0.02% w/v or 200 ppmw/v.

[0142] The polymers were tested for adsorption to cotton fabric using anapparatus for simultaneously contacting different liquids with differentregions of a single sheet of fabric. This apparatus is described indetail in U.S. patent application Ser. No. 09/593,730, filed Jun. 13,2000, which is incorporated herein by reference. Briefly, six sheets offabric were clamped between an upper and lower block. The fabric sheetshad previously been printed with rubbery, cross-linked ink in microtiterplate pattern using standard screen printing techniques and materials.Both blocks contain 8×12 arrays of square cavities, which are alignedwith un-printed regions of the fabrics. When the blocks and fabrics areclamped together, liquids placed in the individual wells do not leak orbleed through to other wells, due to the pressure applied by the blocksin the regions separating the wells, and due to the presence of thecross linked ink in these regions, which fills the pores between thefibers. The liquids are forced to flow back and forth through the fabricby means of a pneumatically actuated thin rubber membrane, which isplaced between the fabrics and the lower block. Repeated flexing of themembrane away from and towards the fabrics results in fluid motionthrough the fabrics.

[0143] Six white cotton fabrics were tested simultaneously in a singleapparatus. 400 μl of the 200 ppm polymer/surfactant solutions wereplaced in the corresponding wells in the apparatus. The liquids wereflowed through the fabrics for 1 hour at room temperature, with a flowcycle time of approximately 0.5 seconds per complete cycle. After onehour, the free liquid in the cells was poured off, and the apparatus wasimmersed briefly in tap water to further remove free polymer solution.The blocks were then separated, and the fabrics were removed, separated,and thoroughly rinsed in 6 liters of tap water. The fabrics were allowedto air dry for 24 hours.

[0144] The amount of adsorbed polymer was determined by fluorescenceimaging. Fluorescence imaging was performed by mounting the sample on astage in a light-tight enclosure. Near-UV excitation (˜365 nm) wasprovided by a pair of 8 watt UV fluorescent lamps mounted above and tothe side of the sample on adjustable mounts. The total irradianceincident upon the sample was ˜1.8 mW/cm² as measured with a calibratedradiometer (Minolta UM-1 w/UM-36 detector). Rejection of undesiredreflected light was performed with a glass bandpass filter (Oriel part #59850) having a center wavelength of 520 nm, maximum transmission of52%, and FWHM bandwidth of 90 nm, mounted directly in front of theimaging lens. The photoluminescence of the samples was collected with aimaging grade lens of 60 mm focal length (Micro Nikkor) and imaged on athermoelectrically cooled, 1152×1242 pixel, front illuminated, researchgrade focal plane array CCD detector (available from PrincetonInstruments) under computer control. The exposure time was 20 seconds.

[0145] The images were analyzed on a computer using a program whichallows the user to define a centroid position for the top left andbottom right library element; centroids for the remaining elements arethen automatically generated using a simple gridding algorithm. The useralso manually defines the size of a rectangular area around eachcentroid which is to be included in the analysis. Both the total numberof counts within the sampled area and the average counts per pixel arecalculated and stored, for each element in the grid. The latter numberis used for comparisons between libraries, since the sampling area isset manually for each image and is not constant from one library to thenext.

[0146] To calibrate the relationship between the amount of adsorbedpolymer and the fluorescence signal, known amounts of the polymers weredeposited on a second piece of fabric. This was done by first preparinga series of solutions at known polymer concentrations, beginning with a1% wt concentration and diluting progressively by factors of two for atotal of eight concentrations. This was done for all eightpoly(DMA-graft-CMA) polymers being tested, for a total of 64 testsolutions, 1 ml of each contained in an 8×8 array of cells in a 2 mlmicrotiter plate. For each solution, 5 ul was pipetted directly onto thecorresponding square of the second fabric, and allowed to dry. The totalamount of polymer deposited can be calculated from the product of thesolution coricentration times the volume deposited (table 2, below). Theaverage mass of fabric in each square is 7.5 mg. The calibration samplewith deposited polymers was imaged in the fluorescence system describedabove under identical conditions to the “test” fabrics containing theadsorbed graft polymers.

[0147] The calibration results are shown in Table 3 and FIG. 3. Thefluorescence measurements for a given polymer concentration wereaveraged over the eight different polymers tested, which all containapproximately the same amount of fluorescent monomer per mass ofpolymer. TABLE 3 volume Mg polymer average std. error, Solution massdeposited, polymer mass One cotton deposited per counts per from 8fraction ul deposited, mg square mass gm cotton pixel samples 1.00E − 025 5.00E − 02 0.0075 6.67E + 00 3.29E + 04 1.90E + 03 5.00E − 03 5 2.50E− 02 0.0075 3.33E + 00 2.43E + 04 5.13E + 02 2.50E − 03 5 1.25E − 020.0075 1.67E + 00 2.09E + 04 3.70E + 02 1.25E − 03 5 6.25E − 03 0.00758.33E − 01 1.95E + 04 2.52E + 02 6.25E − 04 5 3.13E − 03 0.0075 4.17E −01 1.81E + 04 1.45E + 02 3.13E − 04 5 1.56E − 03 0.0075 2.08E − 011.73E + 04 1.34E + 02 1.56E − 04 5 7.81E − 04 0.0075 1.04E − 01 1.74E +04 9.26E + 01 7.81E − 05 5 3.91E − 04 0.0075 5.21E − 02 1.70E + 047.32E + 01 0.00E + 00 5 0.00E + 00 0.0075 0.00E + 00 1.68E + 04 1.13E +02

[0148] Referring to FIG. 3, a straight line was fit to the calibrationdata, yielding the relationship:

counts per pixel=a+b*(mg polymer/gram cotton)=1.7E+04+1.97E+03*(mgpolymer/gram cotton).

[0149] The paramter a gives the number of counts observed for cottonsquares carrying no dye, and contains contributions from the darkcurrent of the CCD, any intrinsic fluorescence from the undyed fabric(including any chemicals used in manufacture and/or processing of thefabric), and any of the UV excitation which passes through the filter.

[0150] In practice the value of a was found to vary slightly from onefabric array to the next, and was determined for each fabric as anaverage divided by (or “over”) all cells not carrying any dye (i.e.,“blanks”). Thus for the test cells, to which the dye-tagged graftpolymers were allowed to adsorb from solution, the amount of adsorbedpolymer was determined from the averaged number of counts per pixel as

mg polymer/gram cotton=(counts per pixel−a)/b

[0151] where the same slope value b=1970 was used for all samples, butthe value of the intercept a was determined from the blanks by averagingfor each 8×12 fabric array tested. The results of processing this dataare shown in FIG. 4 (in units of mg polymer/gram cotton), averaged overall four fabrics tested, and including error bars which represent thestandard error calculated from the four measurements. As FIG. 4demonstrates, the amount of adsorbed polymer decreases gradually as thelength of the grafts is increased over a wide range.

[0152] Separate experiments were done in order to demonstrate that freedye in solution binds weakly or not at all to the cotton fabric, andthat poly(dimethylacrylamide) homopolymers containing dye do not adsorbsignificantly to the cotton fabric.

Example 3 Effect of Graft Architecture on the Adsorbed Amount

[0153] A variety of different polymers were grafted from cellulosemonoacetate (CMA), with different degrees of substitution of the graftsand different degrees of polymerization of the grafts. The monomers usedfor the grafts were dimethylacrylamide (DMA),trishydroxymethylmethylacrylamide (THMMA), Acrylamide methylpropanesulphonic acid triethylamine salt (AMPS:Et3N) and N-carboxymethyldimethylaminopropyl acrylamide (N-carbDMAPA). The graft chains werepresent in seven different degrees of substitution across the bulksample, namely DS of 0.012, 0.023, 0.04, 0.072, 0.125, 0.18 and 0.27.For each of the first 4 degrees of substitution, five graft polymerswere prepared with different degrees of polymerization (DP) of thegrafts, with DP's of 25, 50, 100, 200 and 400 being targeted. For eachof the last 3 degrees of substitution, four graft polymers were preparedwith different degrees of polymerization of the grafts, with DP's of 25,50, 100 and 200 being targeted. The polymerization proceededsubstantially according to the methods of Examples 1 and 2.

[0154] In this example, the control agent was one where “Z” was pyrrole(see scheme 6, above). 0.5 mol % of a fluorescent monomer (structureshown below)

[0155] was incorporated in all the grafts

[0156] during polymerization of the grafts. CMA was used as a 20 wt %solution in DMF. Dimethylacrylamide was used a as 50% solution in DMF.Trishydroxymethylmethylacrylamide was used as a 20% solution in DMF.Acrylamidomethylpropanesulfonicacid triethylamine salt was used as a 20%solution in DMF. N-CarboxymethylDimethylaminopropylacrylamide was usedas a 20% solution in water. AIBN was used as a solution in DMF.

[0157] The following procedure is representative for the synthesis ofall other polymers in this example: For CMA-DS-0.012 and monomer DMA ata DP=25: In an inert N₂ atmosphere CMA (89.21 mg) and dimethylacrylamide(10.79 mg) were mixed in a vial. To this AIBN (0.089 mg) was added andthe mixture was heated to 65° C. and stirred for 18 hrs. The reactionmixture was then diluted to 10 wt % with DMF.

[0158] Other than DMF, the following Tables 4-10 provide the amounts ofreactants used in each polymerization mixture: TABLE 4 DS DPCMA-Pyrrole-0.012 AIBN DMA THMMA AMPS:Et3N N-CarbDMAPA 0.012 25 89.210.089 10.79 0 0 0 0.012 50 80.53 0.161 19.47 0 0 0 0.012 100 67.41 0.2732.59 0 0 0 0.012 200 50.84 0.407 49.16 0 0 0 0.012 400 34.08 0.54665.92 0 0 0 0.012 25 82.41 0.083 0 17.59 0 0 0.012 50 70.09 0.14 0 29.910 0 0.012 100 53.95 0.216 0 46.05 0 0 0.012 200 36.94 0.296 0 63.06 0 00.012 400 22.65 0.363 0 77.35 0 0 0.012 25 72.7 0.073 0 0 27.3 0 0.01250 57.1 0.114 0 0 42.9 0 0.012 100 39.96 0.16 0 0 60.04 0 0.012 20024.97 0.2 0 0 75.03 0 0.012 400 14.27 0.229 0 0 85.73 0 0.012 25 80.310.08 0 0 0 19.69 0.012 50 67.1 0.134 0 0 0 32.9 0.012 100 50.49 0.202 00 0 49.51 0.012 200 33.77 0.271 0 0 0 65.23 0.012 400 20.32 0.325 0 0 079.68

[0159] TABLE 5 DS DP CMA-Pyrrole-0.023 AIBN DMA THMMA N-carbDMAPA AMPS:Etr3N 0.023 25 80.9 0.158 19.1 0 0 0 0.023 50 67.93 0.266 32.07 0 0 00.023 100 51.44 0.402 48.56 0 0 0 0.023 260 34.62 0.541 65.38 0 0 00.023 400 20.94 0.655 79.06 0 0 0 0.023 25 70.59 0.138 0 29.41 0 0 0.02350 54.55 0.213 0 45.45 0 0 0.023 100 37.5 0.293 0 62.5 0 0 0.023 26023.08 0.361 0 76.02 0 0 0.023 400 13.04 0.408 0 86.96 0 0 0.023 25 57.70.113 0 0 0 42.31 0.023 50 40.54 0.159 0 0 0 59.46 0.023 100 25.42 0.1990 0 0 74.58 0.023 260 14.56 0.223 0 0 0 85.44 0.023 400 7.85 0.246 0 0 092.15 0.023 25 67.63 0.132 0 0 32.37 0 0.023 50 51.09 0.2 0 0 48.91 00.023 100 34.31 0.268 0 0 66.69 0 0.023 260 26.71 0.324 0 0 79.29 00.023 400 11.55 0.361 0 0 88.45 0

[0160] TABLE 6 DS DP CMA-Pyrrole-0.04 AIBN DMA THMMA AMPS: Et3NN-carbDMAPA 0.04 25 68.54 0.261 31.46 0 0 0 0.04 50 52.14 0.396 47.86 00 0 0.04 100 35.26 0.536 64.74 0 0 0 0.04 200 21.41 0.651 78.59 0 0 00.04 400 11.99 0.729 88.01 0 0 0 0.04 25 55.24 0.21 0 44.76 0 0 0.04 5038.16 0.29 0 61.84 0 0 0.04 100 23.58 0.359 0 76.42 0 0 0.04 200 13.370.406 0 86.63 0 0 0.04 400 7.16 0.436 0 92.84 0 0 0.04 25 41.22 0.157 00 58.78 0 0.04 50 25.96 0.197 0 0 74.04 0 0.04 100 14.92 0.227 0 0 85.080 0.04 200 8.06 0.245 0 0 91.94 0 0.04 400 4.2 0.255 0 0 95.8 0 0.04 2551.8 0.197 0 0 0 48.2 0.04 50 34.95 0.266 0 0 0 65.05 0.04 100 21.180.322 0 0 0 78.82 0.04 200 11.84 0.36 0 0 0 88.16 0.04 400 6.29 0.383 00 0 93.71

[0161] TABLE 7 DS EP CMA-Pyrrole-0.072 AIBN DMA THMMA N-carbDMAPA AMPS:Et3N 0.072 25 56.79 0.358 43.21 0 0 0 0.072 50 39.66 0.5 60.34 0 0 00.072 100 24.73 0.623 75.27 0 0 0 0.072 200 14.11 0.711 85.89 0 0 00.072 400 7.59 0.765 92.41 0 0 0 0.072 25 42.68 0.269 0 57.32 0 0 0.07250 27.13 0.342 0 72.87 0 0 0.072 100 15.69 0.396 0 84.31 0 0 0.072 20085.14 0.429 0 91.49 0 0 0.072 400 4.45 0.448 0 95.55 0 0 0.072 25 29.730.187 0 0 0 70.27 0.072 50 17.46 0.22 0 0 0 82.54 0.072 100 9.56 0.241 00 0 90.44 0.072 200 5.02 0.253 0 0 0 94.98 0.072 400 25.8 0.26 0 0 097.42 0.072 25 39.33 0.248 0 0 60.67 0 0.072 50 24.48 0.309 0 0 75.52 00.072 100 13.94 0.352 0 0 86.06 0 0.072 200 7.5 0.378 0 0 92.5 0 0.072400 3.89 0.393 0 0 96.11 0

[0162] TABLE 8 DS DP CMA-Pyrrole-0.18 AIBN DMA THMMA N-carbDMAPA AMPS:EtB3N 0.125 25 43.69 0.466 56.31 0 0 0 0.125 50 27.95 0.597 72.05 0 0 00.125 100 16.25 0.694 83.75 0 0 0 0.125 200 8.84 0.755 91.16 0 0 0 0.12525 30.53 0.325 0 69.47 0 0 0.125 50 18.02 0.385 0 81.98 0 0 0.125 1009.9 0.423 0 90.1 0 0 0.125 200 5.21 0.445 0 94.79 0 0 0.125 25 19.980.213 0 0 0 80.02 0.125 50 11.1 0.237 0 0 0 88.9 0.125 100 5.88 0.251 00 0 94.1 0.125 200 3.03 0.259 0 0 0 96.97 0.125 25 27.68 0.295 0 0 72.320 0.125 50 16.06 0.343 0 0 83.94 0 0.125 100 8.73 0.373 0 0 91.27 00.125 200 4.57 0.39 0 0 95.43 0

[0163] TABLE 9 DS DP CMA-Pyrrole-0.18 AIBN DMA THMMA N-carbDMAPA AMPS:Et3N 0.18 25 38.56 0.509 61.44 0 0 0 0.18 50 23.89 0.63 76.11 0 0 0 0.18100 13.56 0.716 86.44 0 0 0 0.18 200 7.28 0.768 92.72 0 0 0 0.18 2526.23 0.346 0 73.77 0 0 0.18 50 15.09 0.398 0 84.91 0 0 0.18 100 8.160.431 0 91.84 0 0 0.18 200 4.26 0.449 0 95.74 0 0 0.18 25 16.81 0.222 00 0 83.19 0.18 50 9.17 0.242 0 0 0 90.83 0.18 100 4.81 0.254 0 0 0 95.190.18 200 2.46 0.26 0 0 0 97.54 0.18 25 23.64 0.312 0 0 76.36 0 0.18 5013.4 0.354 0 0 86.6 0 0.18 100 7.18 0.379 0 0 92.82 0 0.18 200 3.730.393 0 0 96.27 0

[0164] TABLE 10 DS DP CMA-Pyrrole-0.27 AIBN DMA THMMA N-carbDMAPA AMPS:Et3N 0.27 25 32.35 0.56 67.65 0 0 0 0.27 50 19.3 0.668 80.7 0 0 0 0.27100 10.68 0.74 89.32 0 0 0 0.27 200 5.64 0.782 94.36 0 0 0 0.27 25 21.320.369 0 78.68 0 0 0.27 50 11.93 0.413 0 88.07 0 0 0.27 100 6.34 0.439 093.66 0 0 0.27 200 3.28 0.454 0 96.72 0 0 0.27 25 13.34 0.231 0 0 086.66 0.27 50 7.15 0.248 0 0 0 92.85 0.27 100 3.71 0.257 0 0 0 96.290.27 200 1.89 0.262 0 0 0 98.11 0.27 25 19.08 0.331 0 0 80.92 0 0.27 5010.55 0.365 0 0 89.45 0 0.27 100 5.57 0.386 0 0 94.43 0 0.27 200 2.860.397 0 0 97.14 0

[0165] Conversions were spot checked by NMR for selected samples andgraft polymers of DMA and TRIS were analyzed by aqueous GPC. The DS forgrafts across the bulk sample was measured by NMR according to thediscussion in this specification. Each polymerization resulted in acellulose monoacetate graft polymer. The amount of monomer in thepolymerization mixture determined the graft length.

[0166] Using the parallel deposition contacting apparatus and methoddescribed in Example 2, after synthesis, the reaction mixtures weretopped off with solvent to bring the total polymer concentration to anominal value of 12.5 wt % in all wells (100 mg polymer in 800 ulsolvent). These solutions were used without any subsequent purificationto remove solvent, unreacted monomer, etc. The polymers were diluted intwo steps to achieve an ultimate concentration of 200 ppm by weight in abuffered surfactant solution. The composition of the surfactant solutionis as follows, with the solvent being demineralized water:

[0167] 0.6 g/L LAS anionic surfactant

[0168] 0.4 g/L R(EO)₇

[0169] 1.25 g/L Na₂CO₃— JT Baker #3604-01

[0170]0.66 g/L STP

[0171]0.6 g/L NaCl

[0172] 0.0882 g/L CaCl₂ 2H₂O— Sigma #C-8106

[0173] pH=10.5.

[0174] In the first dilution step, 32 ul of each polymer solution wasadded to 2 ml of the surfactant solution, in a 2 ml capacity 96-wellpolypropylene microtiter plate. This gave an initial dilution of 1:62.5,for a polymer concentration of 0.2 wt %. The solutions were mixed bymulti-well magnetic stirring. In the second dilution step, 40 ul of the0.2 wt % solutions and 360 ul of the surfactant solution were addedtogether directly in the apparatus used for screening adsorption inparallel format (described in Example 2). The final polymerconcentration is thus a nominal 0.02 wt % or 200 ppm by weight.

[0175] The liquids (sample/surfactant solutions) were flowed through thefabrics for 1 hour at room temperature, with a flow cycle time ofapproximately 0.5 seconds per complete cycle. After one hour, the freeliquid in the cells was poured off, and the apparatus was immersedbriefly in tap water to further remove free polymer solution. The blockswere then separated, and the fabrics were removed, separated, andthoroughly rinsed in 6 liters of tap water. The fabrics were allowed toair dry for 24 hours.

[0176] Each square of the test fabrics has a mass of approximately 7.5mg, so the total fabric mass per well is approximately 45 mg. The massof sample/surfactant solution in each well is approximately 400 mg (400ul volume), containing a polymer mass fraction of 0.02% or a polymermass of 0.08 mg. Thus the maximum amount of polymer which can bedeposited on the fabric is 0.08 mg/45 mg=1.8 mg polymer per gram offabric. In order to calculate from the fluorescence signals the amountof polymer actually deposited from the wash, additional fabrics wereprepared by directly depositing controlled amounts of the polymers onsquares of the test fabrics. The solutions at 0.2 wt % polymer were usedfor this purpose. A volume of approximately 3.5 ul of each solution wasdeposited, carrying a total polymer mass of 0.007 mg and giving polymerdeposition relative to the fabric in the amount (0.007 mg polymer persquare)/(7.5 mg fabric per square)≈0.9 mg/gm. This is one half themaximum possible amount of polymer that could be deposited under thetest conditions.

[0177] The amount of deposited polymer was determined by fluorescenceimaging as described in Example 2, but in this example, the f-stop valuewas f4 and the exposure time was 500 msec. A background image wasobtained by taking an exposure with the UV illumination turned off. Theeffects of non-uniform UV illumination were accounted for by imaging auniform fluorescent target (Peel-N-Stick Glow Sheeting, manufactured byExtremeGlow, http://www.extremeglow.com) under the same irradiation andexposure conditions used for imaging the fabrics. The number of countsin a pixel in an experiment image was corrected by first subtracting thenumber of counts in the corresponding background image pixel, and thendividing by the number of counts in the corresponding uniform targetimage pixel.

[0178] The corrected images were analyzed on a computer using a programthat allows the user to define a centroid position for the top left andbottom right library element. Centroids for the remaining elements arethen automatically generated using a simple gridding algorithm. The useralso manually defines the size of a circular area around each centroidwhich is to be included in the analysis. Both the total number of countswithin the sampled area and the average counts per pixel are calculatedand stored, for each element in the grid. The latter number is used forcomparisons between libraries, since the sampling area is set manuallyand is not necessarily constant from one library to the next. See, forexample, WO 00/60529 for disclosure of such a program, which isincorporated herein by reference.

[0179]FIG. 5 shows a subset of the data, where DS is equal to 0.023(FIG. 5A) and 0.18 (FIG. 5B). The lower points in each plot representthe signal from the experimental samples, and the upper points (shown astriangles “▴”) represent twice the signal from the control samples,i.e., the signal which would occur if all polymer were deposited. Theupper points thus represent the amount of graft available in solution,and the lower points represent the amount of graft actually deposited onthe fabric from the deposition step. From FIG. 5A, the amount ofdeposited grafted polymer reaches a maximum at about DP=100 and thendecreases, even though the amount of graft available for depositioncontinues to increase. From FIG. 5B, the amount of deposited graftpolymer is much less than for DS=0.023, even though the amount ofavailable graft is in all cases larger. Also the amount of depositedpolymer essentially decreases monotonically with increasing DP, eventhough the amount of available graft is increasing monotonically.Similar data was obtained for the other tested graft polymers in thisexample, for example for dimethylacrylamide grafts, with DS values of0.012 and 0.125, the trends of available vs. adsorbed polymer weresimilar to those observed for THMMA grafts.

[0180]FIG. 6 summarizes the results for all of the polymers with THMAgrafts. The x-axis is the number of grafts per chain (=DS*100) and they-axis is the targeted graft degree of polymerization, DP. The size ofthe data points is proportional to twice the signal from the “control”sample, and the relative shade of the data points represents thefluorescence signal from the experimental samples. The size of thepoints increases monotonically with both DP and DS, because the graftmakes up a larger fraction of the polymer as each of these variablesincreases. The region where the point interiors are lighter representsthe region in which the deposition of the grafts is optimized ormaximized. An oval has been drawn in FIG. 6 around the region where ananti-correlation exists between the optimum values of DS and DP—as DS isincreased, the value of DP which gives optimum deposition. decreases,which represents the approximate region where strong deposition occurs.Thus in some embodiments a graft copolymer having a DS of from 0.1 to1.0 and a DP from 5 to 50 is within the scope of this invention.

[0181] It is to be understood that the above description is intended tobe illustrative and not restrictive. Many embodiments will be apparentto those of skill in the art upon reading the above description. Thescope of the invention should, therefore, be determined not withreference to the above description, but should instead be determinedwith reference to the appended claims, along with the full scope ofequivalents to which such claims are entitled. The disclosures of allarticles and references, including patent applications and publications,are incorporated herein by reference for all purposes.

What is claimed is:
 1. A graft polymer comprising, a cellulosic backboneand a plurality of graft chains extending from said backbone, each ofsaid plurality of grafts chains having a degree of polymerizationbetween 25 and 250; wherein said graft polymer is substantially free ofcross-linking and has a degree of substitution of grafts across a bulksample in the range of from 0.02 to 0.2.
 2. The graft polymer of claim1, wherein the number of grafts ranges from about 3 to about 12 percellulosic backbone.
 3. The graft polymer of claim 1, wherein the graftson the cellulosic backbone have a degree of polymerization of between 50and
 100. 4. The graft polymer of claim 1, wherein said graft chains arehomopolymers or copolymers.
 5. The graft polymer of claim 1, whereinsaid cellulosic backbone is xyloglucan, locust bean gum, glucomannan orcellulose monoacetate.
 6. The graft polymer of claim 1, wherein saidcellulosic backbone has a number average molecular weight from about10,000 to about 40,000.
 7. The graft polymer of claim 1, wherein saidpolymer is water soluble at a concentration of at least about 0.2 mg/mL.8. A graft copolymer comprising a cellulosic backbone and a plurality ofgraft chains extending from said backbone, each of said plurality ofgrafts chains having a degree of polymerization between 5 and 50;wherein said graft polymer is substantially free of cross-linking andhas a degree of substitution of grafts across a bulk sample in the rangeof from 0.1 to 1.0.
 9. A compound characterized by the following thegeneral formula:

where SU represents a sugar unit in a cellulosic backbone, L is anoptional linker, Y is a control agent site from which a polymer maypropagate during a free radical polymerization reaction, a is in therange of from about 3-80, b is in the range of from about 1-25, c is 0or 1, and d is 1-3.
 10. The compound of claim 9, wherein Y ischaracterized by at least one of the following formulas:

where Z is any group that activates the C═S double bond towards areversible free radical addition fragmentation reaction and R″ isselected from the group consisting of optionally substituted hydrocarbyland heteroatom-containing hydrocarbyl, and the group is attached to thelinker or sugar unit via either the Z or R″ groups; or (2) —I—O—NR⁵R⁶,wherein I is an initiating fragment and each of R⁵ and R⁶ isindependently selected from the group of hydrocarbyl, substitutedhydrocarbyl, heteroatom containing hydrocarbyl and substitutedheteroatom containing hydrocarbyl; and optionally R⁵ and R⁶ are joinedtogether in a ring structure.
 11. The compound of claim 10, wherein Z isselected from the group consisting of hydrocarbyl, substitutedhydrocarbyl, heteroatom-containing hydrocarbyl and substitutedheteroatom containing hydrocarbyl.
 12. The compound of claim 11, whereinZ is selected from the group consisting of optionally substituted alkyl,aryl, heteroaryl, amino and alkoxy.
 13. The compound of claim 10,wherein Y is characterized by the second formula (2), which includes amolecule characterized by the general formula:

where the I residue is selected from the group consisting of fragmentsderived from a free radical initiator, alkyl, substituted alkyl, alkoxy,substituted alkoxy, aryl, substituted aryl, and combinations thereof; Xis a moiety that is capable of destabilizing the control agent on apolymerization time scale; and each R¹ and R², independently, isselected from the group consisting of optionally substituted alkyl,heteroalkyl, aryl, heteroaryl, alkoxy, aryloxy, silyl, boryl, phosphino,amino, thio, seleno, and combinations thereof; and R³ is selected fromthe group consisting of optionally substituted tertiary alkyl, aryl,tertiary heteroalkyl, heteroaryl, alkoxy, aryloxy and silyl.
 14. Thecompound of claim 9, wherein c is 1 and said linker L comprises from 2to 50 non-hydrogen atoms.
 15. The compound of claim 14, wherein saidlinker is selected from the group of diisocyanates, urethanes, andamides.
 16. The compound of claim 9, wherein c is 0 such that the Ycontrol agent is attached directly to the sugar unit.
 17. A polymercomprising, a polymeric backbone selected from the group consisting ofcellulose, modified cellulose and hemi-cellulose; and at least onependant polymeric chain attached to said polymeric backbone, whereinsaid at least one chain comprises a control agent moiety that isselected from the group consisting of

 where Z is selected from the group consisting of optionally substitutedalkyl, alkenyl, alkynyl, aralkyl, alkaryl, heteroalkyl, heteroalkenyl,heteroalkynyl, alkoxy, aryl, heteroaryl, amino; R″ is selected from thegroup consisting of optionally substituted hydrocarbyl andheteroatom-containing hydrocarbyl, and the group is attached to thelinker or sugar unit via either the Z or R″ groups; and  (2) —O—NR⁵R⁶,wherein each of R⁵ and R⁶ is independently selected from the group ofhydrocarbyl, substituted hydrocarbyl, heteroatom containing hydrocarbyland substituted heteroatom containing hydrocarbyl; and optionally R⁵ andR⁶ are joined together in a ring structure.
 18. The polymer of claim 17,wherein on average there are between 0.5 and 25 pendant polymeric chainsattached to said polymeric backbone.
 19. The polymer of claim 17,wherein said grafts have a number average molecular weight of from 100to 10,000,000 Da.
 20. The polymer of claim 17, wherein said cellulosicbackbone has a number average molecular weight of from about 3,000 toabout 100,000.
 21. The polymer of claim 17, wherein said pendantpolymeric chains are attached to said polymeric backbone at a siteselected from the group consisting of a terminus of said polymericbackbone and a mid-point of said polymeric backbone and combinationsthereof.
 22. The polymer of claim 17, wherein said polymer is selectedfrom the group consisting of block copolymers and graft copolymers. 23.The polymer of claim 17, wherein said cellulosic backbone is xyloglucan,locust bean gum, glucomannan or cellulose monoacetate.
 24. A process forpreparing cellulosic polymers, comprising: (a) attaching at least onecontrol agent to a polymeric backbone selected from the group consistingof cellulose, modified cellulose and hemi-cellulose; said control agentmoiety being selected from the group consisting of

 where Z is selected from the group consisting of optionally substitutedalkyl, alkenyl, alkynyl, aralkyl, alkaryl, heteroalkyl, heteroalkenyl,heteroalkynyl, alkoxy, aryl, heteroaryl, amino; R″ is selected from thegroup consisting of optionally substituted hydrocarbyl andheteroatom-containing hydrocarbyl, and the group is attached to thelinker or sugar unit via either the Z or R″ groups; and  (2) —I—O-NR⁵R⁶,wherein I initiates free radical polymerization upon cleavage of the I—Obond an each of R⁵ and R⁶ is independently selected from the group ofhydrocarbyl, substituted hydrocarbyl, heteroatom containing hydrocarbyland substituted heteroatom containing hydrocarbyl; and optionally R⁵ andR⁶ are joined together in a ring structure; and (b) polymerizing atleast one free radically polyrnerizable monomer from the point ofattachment of said at least one control agent.
 25. The process of claim24, wherein said cellulosic backbone is depolymerized prior toattachment of said at least one control agent.
 26. The process of claim24, wherein said point of attachment of said at least one control agentis at a site selected from the group consisting of a terminus of saidpolymeric backbone and a mid-point of said polymeric backbone andcombinations thereof.
 27. The process of claim 24, wherein saidpolymeric backbone is subjected to either hydrolysis or saponificationeither prior to or after said attachment step.
 28. The process of claim24, wherein said polymerization step produces a polymeric segmentattached to said polymeric backbone, wherein the molecular weight ofsaid polymeric segment is controlled to a desired point based on saidliving-type kinetics.
 29. The process of claim 24, wherein saidpolymerization occurs under polymerization conditions comprising asource of free radical initiation, a polymerization time of from 0.5hours to 72 hours and a temperature above 20° C.
 30. The process ofclaim 29, wherein said polymerization step is carried out to aconversion of at least 50%.
 31. The process of claim 24, wherein saidcontrol agent is the dithio compound and said process additionallycomprises cleaving said control agent from said polymer after saidpolymerization step.